Operating sequence per unit : During production DC Isolator HSE/HSD and DC Braker HSLT are in ON position . In case of maintenance of one unit only the cell has to switch OFF.
First step : DC ON-Load HSLT has to switch off – second step : DC OFF-Load has to switch off. The right switch-sequence guarantees the locking system.

Bi-Polar- Membran Technology

There are some cell suppliers , who install per cellunit two DC Isolators HSE/HSD

and one DC Breaker HSLT. In this application the two DC Isolator are in ON position during production and the DC Breaker is in OFF position only. In case of maintenance at first the ON-Load switch will switch in ON position and second step the two OFF Load switches will switch in OFF position. The right switch sequence guarantees a locking system.

For further information: In some new plants there are only DC OFF LOAD Isolators in plus-and minus pole. Each cell group is electrical supplied by an own rectifier.

The switch equipment is certificated by IPH Institutes in Berlin – Germany

The switches are in accordance with IEC 047-1 ; IEC 947-2

DC- Breaker HSLT

Description High CurrentDC-Breaker HSLT

The high current DC-breakers HSLT consist of a contact system with one or more integrated, encapsulated contact modules, the lateral mounted pre-contact, and the operating mechanism. The construction of the main contact system is identical to the isolators HSE. The pre-contact is actuated by the main switching shaft of the breaker. This combination allows switching under load conditions up to a rated current of 30 kA at a rated voltage of 500 VDC. When switching on, first a spring of the pre-contact is charged, and after exceeding the cut-off point, the pre-contact is rapidly closed independent of the operating speed. Afterwards the main contacts are closed. During OFF-operation, first the main contacts are interrupted and afterwards, again by means of a charged spring, the pre-contact is opened. This operation sequence makes sure that the rnain contacts are operated with no load and the rated current is carried by the pre-contact for a short time only.

For arc extinction during the OFF-cycle, the pre-contact is equipped with an arc chamber which will safely quench the electric arc.

The DC-breaker has to be installed vertically that mean that the arc chamber for a safe arc extinction has to be upright.

The ON-OFF position is indicated by means of a mechanical position indicator and for electrical indication 1 NO 1NC contact for each position is provided. Further auxiliarj contacts, also for the control of the blocking magnet of the isolator HSE, can be installed (up to a maximum of 6NO 6NC). These auxiliary contacts are mounted in the terminal box and are directly connected to the control. Further electrical components of the breaker are connected to terminals inside the terminal box.

Operating Mechanism:

The design of the switches ( ball bearings supported main switching shaft ) and the very little travel of the contacts while switching, require only a little operating force. Thus easy manual operation is possible or operation by means of a directing acting motor operator with little power consumption. Pressure air operators with rotating cylinders are also available. Under all circumstances switching is done over dead center, so a safe operation is always guaranteed.

For emergency operation of remote controlled breakers, an emergency operating device is provided.

Features:

complete encapsulated main contacts

high mechanical strength

corrosion proofed

little operation torques

positive opening

low contact resistance

low voltage drop

low contact heating

extreme high electrical and mechanical durability

safe operation, even under extreme ambient temperature

DC Trenner HSE

Description High Current Isolators HSE

The high current isolators HSE consist of a contact system with one or more integrated, encapsulated contact modules. One module is normally rated for a current of 6,000 Amps. If higher ratings are required, adequate numbers of contact rnodules are connected in parallel and operated with a common mechanism. The principal item of the switches are standardized, encapsulated contacts, which consist of two connector plates, a high-elastic bellow, and the contacts. These contacts are made of silver alloy with very good electrical data. The isolators allow an installation in any position directly into the busduct system without further fixation. One side of the switch is equipped with flexible copper connectors, thus no further expansion joints have to be provided. The other side has solid copper bus bars. The ON-OFF position is indicated by rneans of a mechanical position indicator and for electrical indication 1NO 1NC contact for each position is provided. Further auxiliary contacts (up to a maximum of 6NO 6NC) can be installed. These auxiliary contacts are rnounted in the terminal box and are directly connected to the control.

Operating Mechanisms:

The design of the switches (ball bearings supported main switching shaft) and the very little travel of the contacts while switching, require only a little operating force. Thus easy manual operation is possible or operation by means of a directing acting motor operator with little power consumption. Pressure air operators with rotating cylinders are also available. Under all circumstances switching is done over dead center, so a safe operation is always guaranteed.

To eliminate contact burn of the main contacts due to residual voltage of the cells, always pre-contacts should be provided. These pre-contacts close before the main contacts are closed and open afterwards opening of the main contacts.